Search Images Maps Play YouTube News Gmail Drive More »
Sign in
Screen reader users: click this link for accessible mode. Accessible mode has the same essential features but works better with your reader.

Patents

  1. Advanced Patent Search
Publication numberUS5201215 A
Publication typeGrant
Application numberUS 07/779,727
Publication dateApr 13, 1993
Filing dateOct 17, 1991
Priority dateOct 17, 1991
Fee statusPaid
Publication number07779727, 779727, US 5201215 A, US 5201215A, US-A-5201215, US5201215 A, US5201215A
InventorsVictoria E. Granstaff, Stephen J. Martin
Original AssigneeThe United States Of America As Represented By The United States Department Of Energy
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Method for simultaneous measurement of mass loading and fluid property changes using a quartz crystal microbalance
US 5201215 A
Abstract
A method, using a quartz crystal microbalance, to obtain simultaneous measurement of solid mass accumulation and changes in liquid density-viscosity product. The simultaneous real-time measurements of electrical parameters yields that changes in surface mass can be differentiated from changes in solution properties. Two methods to obtain the admittance/frequency data are employed.
Images(5)
Previous page
Next page
Claims(8)
What is claimed is:
1. A method to determine total mass of a solid and physical properties of a fluid, contacting the same quartz crystal microbalance, comprising:
(a) applying an oscillating electric field across the thickness of said quartz crystal microbalance;
(b) measuring at least one resonant frequency of said quartz crystal microbalance;
(c) simultaneously measuring the admittance magnitude at said resonant frequencies to characterize an unperturbed state;
(d) applying a solid mass and a fluid onto said quartz crystal microbalance where said quartz crystal microbalance is in contact with said solid mass interposed between said quartz crystal microbalance and said fluid to produce a perturbed state;
(e) measuring at least one resonant frequency of said quartz crystal microbalance in said perturbed state;
(f) simultaneously measuring the admittance magnitude of said quartz crystal microbalance in said perturbed state;
(g) correlating changes in said resonant frequencies and changes in said admittance magnitudes of said unperturbed states to obtain a surface mass density and a fluid viscosity-density product.
2. The method of claim 1, wherein said resonant frequency is a fundamental frequency.
3. The method of claim 1, wherein said resonant frequency is a fundamental and a harmonic frequency.
4. A method to determine total mass contacting a quartz crystal microbalance comprising:
(a) applying an oscillating electric field across the thickness of said quartz crystal microbalance;
(b) measuring at least one resonant frequency of said quartz crystal microbalance;
(c) simultaneously measuring the admittance magnitude at said resonant frequencies to characterize an unperturbed state;
(d) applying a solid mass onto said quartz crystal microbalance where said quartz crystal microbalance is in contact with said solid mass to produce a perturbed state;
(e) measuring at least one resonant frequency of said quartz crystal microbalance in said perturbed state;
(f) simultaneously measuring the admittance magnitude of said quartz crystal microbalance in said perturbed state;
(g) correlating changes in said resonant frequencies and changes in said admittance magnitudes of said unperturbed and perturbed states to obtain a surface mass density.
5. A method to determine physical properties of a fluid contacting a quartz crystal microbalance, comprising:
(a) applying an oscillating electric field across the thickness of said quartz crystal microbalance;
(b) measuring at least one resonant frequency of said quartz crystal microbalance;
(c) simultaneously measuring the admittance magnitude at said resonant frequencies to characterize an unperturbed state;
(d) applying a fluid onto said quartz crystal microbalance where said quartz crystal microbalance is in contact with said fluid to produce a perturbed state;
(e) measuring at least one resonant frequency of said quartz crystal microbalance in said perturbed state;
(f) simultaneously measuring the admittance magnitude of said quartz crystal microbalance in said perturbed state;
(g) correlating changes in said resonant frequencies and changes in said admittance magnitudes of said unperturbed and perturbed states to obtain a fluid viscosity-density product.
6. A method to determine total mass contacting a quartz crystal microbalance, and physical properties of a fluid in contacting said quartz crystal microbalance, comprising:
(a) applying a series of oscillating electric fields of varying frequency across the thickness of said quartz crystal microbalance where said field frequencies are over a range which spans at least one resonant frequency of said crystal;
(b) measuring the magnitude and phase of the admittance over said frequency range;
(c) correlating said admittance data to said frequency, and fitting said admittance and said frequency data to and equivalent circuit model to characterize and unperturbed QCM state;
(d) contacting a solid mass and a fluid onto said crystal, said solid mass interposed between said crystal and said fluid;
(e) repeating steps (b) and (c);
(f) correlating said admittance data to said frequency, and fitting said admittance and said frequency data to an equivalent circuit model to characterize an perturbed QCM state;
(g) extracting solid mass and fluid density-viscosity product from relating said characterized data of said QCM in unperturbed and perturbed states.
7. A method to determine physical properties of a fluid contacting said quartz crystal microbalance, comprising:
(a) applying a series of oscillating electric fields of varying frequency across the thickness of said quartz crystal microbalance where said field frequencies are over a range which spans at least one resonant frequency of said crystal;
(b) measuring the magnitude and phase of the admittance over said frequency range;
(c) correlating said admittance data to said frequency, and applying said admittance/frequency correlation to an equivalent circuit model to characterize an unperturbed QCM state;
(d) contacting a fluid onto said crystal;
(e) repeating steps (b) and (c);
(f) correlating said admittance data to said frequency, and applying said admittance/frequency correlation to an equivalent circuit model to characterize a perturbed QCM state;
(g) extracting fluid density-viscosity product from said correlated admittance and said frequency data from said unperturbed and said perturbed QCM states.
8. A method to determine total solid mass contacting a quartz crystal microbalance, comprising:
(a) applying a series of oscillating electric fields of varying frequency across the thickness of said quartz crystal microbalance where said field frequencies are over a range which spans at least one resonant frequency of said crystal;
(b) measuring the magnitude and phase of the admittance over said frequency range;
(c) correlating said admittance data to said frequency, and applying said admittance/frequency correlation to an equivalent circuit model to characterize an unperturbed QCM state;
(d) contacting a mass onto said crystal, and solid mass oscillating synchronously with said crystal;
(e) repeating steps (b) and (c);
(f) correlating said admittance data to said frequency, and applying said admittance/frequency correlation to an equivalent circuit model to characterize a perturbed QCM state;
(g) extracting solid mass from said correlated admittance and said frequency data from said unperturbed and said perturbed QCM states.
Description

The U.S. Government has rights in this invention pursuant to Contract No. DE-AC04-76DP00789 between the Department of Energy and American Telephone & Telegraph Company.

BACKGROUND OF THE INVENTION

This invention relates generally to the field of microchemical sensors, and more particularly to using electrical parameters to differentiate changes in surface mass from changes in chemical solution properties using a quartz crystal microbalance.

The quartz crystal microbalance (QCM) is commonly configured with electrodes on both sides of a thin disk of AT-cut quartz. Because of the piezoelectric properties and crystalline orientation of the quartz, the application of a voltage between these electrodes results in a shear deformation of the crystal. The crystal can be electrically excited into resonance when the excitation frequency is such that the crystal thickness is an odd multiple of half the acoustic wavelength. At these frequencies, a standing shear wave is generated across the thickness of the plate for the fundamental and higher harmonic resonances.

QCMs were originally used in vacuo to measure deposition rates. As shown by Sauerbrey, Z. PHYS., Vol. 155, pp. 206-222 (1959), changes in the resonant frequency are simply related to mass accumulated on the crystal, and this teaching has been implemented in U.S. Pat. No. 4,788,466, entitled "Piezoelectric Sensor Q-loss Compensation," to Paul et al., Nov. 29, 1988; and U.S. Pat. No. 4,561,286, entitled "Piezoelectric Contamination Detector," to Sekler et al., Dec. 31, 1985; and U.S. Pat. No. 4,391,338, entitled "Microbalance and Method for Measuring the Mass of Matter Suspended Within a Fluid Medium," to Patashnick et al., Jul. 5, 1983. Lu et al., J. APPL. PHYS.Vol. 43, pp. 4385-4390 (1972) showed that the QCM typically may be used as an instrument in the frequency-control element of an oscillator circuit; a precise microbalance is realized by monitoring changes in oscillation frequency. More recently, QCMs have been shown to operate in contact with fluids by Numura et al., NIPPON KAGAKU KAISHI, pp. 1121(1980) enabling their use as solution phase microbalances. This microbalance capability has facilitated a number of solution measurements, as in, for instance, U.S. Pat. No. 4,741,200, entitled "Method and Apparatus for Measuring Viscosity in a Liquid Utilizing a Piezoelectric Sensor," to Hammerle, May 3, 1988. Other examples include deposition monitoring as taught by Schumacher, ANGEW. CHEM. INT. ED. ENGL., Vol. 29, pp. 329-343 (1990), and U.S. Pat. No. 4,311,725, entitled "Control of Deposition of Thin Films," by Holland, Jan. 19, 1982; species detection by Deakin et al., ANAL. CHEM., Vol. 61, pp. 290-295 (1989); immunoassay by Thompson et al., ANAL. CHEM. Vol. 58, pp. 1206-1209 (1986), and U.S. Pat. No. 4,999,284, entitled "Enzymatically amplified piezoelectric specific binding assay," to Ward et al., Mar. 12, 1991; fluid chromatographic detection shown by Konash et al., ANAL. CHEM., Vol. 52, pp. 1929-1931 (1980); corrosion monitoring by Seo et al., EXTENDED ABSTRACTS--178TH MEETING OF THE ELECTROCHEMICAL SOCIETY, Abstract No. 187, p. 272, Seattle, WA (1990); and electrochemical analysis taught by Bruckenstein et al., J. ELECTROANAL. CHEM., Vol. 188, pp. 131-136 (1988), and by Ward et al., SCIENCE, Vol. 249, pp. 1000-1007 (1990).

Kanazawa et al., ANAL. CHEM., Vol. 57, pp. 1770-1771 (1985), have shown that QCMs operating in solution are also sensitive to the viscosity and density of the contacting solution. Viscous coupling of the fluid medium to the oscillating device surface results in both a decrease in the resonant frequency of the QCM and damping of the resonance.

But, prior to the invention described herein, no one has suggested that the mass and the liquid properties can be measured simultaneously. In fact, no one thought that the measurement of mass loading onto a QCM would be affected by the changes in the density and viscosity of the liquid. Indeed, the prior art assumed the fluid density to be constant. But, because the resonant frequency is affected by both mass and fluid loading, measurement of the resonant frequency alone cannot distinguish changes in surface mass from changes in solution properties. Those of the prior art who measured the viscosity or the density of the fluid simply did not have the means to measure the solid mass accumulation. In fact, their measurement of the fluid properties would be in error if there were any solid mass accumulation on the surface of the QCM. And, those in the prior art measuring solid mass accumulation had to assume that the fluid properties remained constant, otherwise their measurement of mass would be in error. But, in fact, the change in frequency is dependent upon both the mass and the fluid properties, and by measuring specific electrical characteristics over a range of frequencies near resonance, the QCM can differentiate between these loading mechanisms.

It is thus an object of the invention to present a QCM simultaneously loaded by a thin surface mass layer and a viscous fluid. The invention takes advantage of the derived analytical expression for QCM admittance as a function of excitation frequency.

Accordingly, the invention is a method to determine total mass of a solid and/or physical properties of a fluid, both the mass and fluid contacting the same quartz crystal microbalance, comprising applying an oscillating electric field across the thickness of the quartz crystal microbalance in contact with a solid mass interposed between the quartz crystal microbalance and a fluid, then measuring at least one resonant frequency of the quartz crystal microbalance, simultaneously measuring the admittance magnitude at the resonant frequencies, and correlating the resonant frequency and the admittance magnitude to obtain a surface mass density and a fluid viscosity-density product. A second embodiment of the invention comprises applying an oscillating electric field across the thickness of a quartz crystal microbalance, sweeping a frequency over a range that spans at least one resonant frequency of the crystal, measuring the magnitude and phase of the admittance over the frequency range, correlating the admittance data to the frequency, and applying the admittance/frequency correlation to an equivalent circuit model, contacting a solid mass and/or a fluid onto the crystal wherein the solid mass is interposed between the crystal and the fluid, repeating the steps sweeping the frequency range that spans a resonant frequency, measuring the magnitude and phase of the admittance over that frequency range, and correlating the admittance data to the frequency and then applying the admittance/frequency correlation to an equivalent circuit model, and then extracting the solid mass and fluid density-viscosity product from the correlated admittance/frequency data.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side and bottom view of the test fixture used for electrical admittance measurements of the QCM with a mass layer and/or fluid contacting the device.

FIG. 2 is a cross-sectional view of a QCM simultaneously loaded on one side by a surface mass layer and a contacting fluid.

FIG. 3 shows the equivalent circuit for a QCM under mass and liquid loading.

FIG. 4 shows QCM admittance measured (points) and calculated (lines) near the fundamental resonance as the density-viscosity product (ρη, g2 /cm4 -s) of a contacting fluid increases.

FIG. 5 shows the QCM admittances measured (points) and calculated (lines) before and after deposition of a thin layer of gold.

DESCRIPTION OF THE INVENTION

FIG. 1 depicts the cross-sectional geometry of the QCM 10 loaded from above by a surface mass layer 20 and a contacting fluid 22. Excitation electrodes 24 and 26 are also located at the upper and lower quartz surfaces, 28 and 30, respectively. The mass layer 20 is on top of the QCM 10 and may or may not be derived from the contacting fluid 22. The mass layer 20 is thin compared to the acoustic wavelength, it is solid and rigidly attached to the QCM 10, ensuring synchronous motion with the oscillating surface. The mass layer 20 may be, for example, metals, metal alloys, salts, some rigid polymers, or ice. The mass layer 20 may be applied to the QCM 10 by evaporation, electroplating, precipitation, or other chemical or thermodynamic reaction. When the contacting fluid 22 contacts this oscillating surface, a damped shear wave is radiated into the fluid, as shown in FIG. 2. QCM surface displacement causes synchronous motion of the surface mass layer and entrainment of the contacting fluid. As long as the fluid thickness is large compared to the decay length of the radiated shear wave, the fluid may be considered semi-infinite.

Coupling between mechanical displacement and electrical potential in the piezoelectric quartz causes mechanical interactions between the QCM and contacting media to influence the electrical characteristics of the QCM, particularly near resonance, where the amplitude of crystal oscillation is greatest. The QCM electrical characteristics can be evaluated using the electrical admittance. Admittance is defined as the ratio of current flow to applied voltage, and may be considered to be the reciprocal of impedance. This parameter contains information about the energy stored and the power dissipated in both the QCM and the perturbing media. The admittance of the QCM is obtained by solving a boundary-value problem that includes the mass layer and contacting fluid.

FIG. 3 shows an equivalent circuit model that describes the electrical admittance of the QCM simultaneously loaded by mass and a contacting liquid. The impedance elements in the equivalent circuit model can be related to the properties of the QCM, the mass layer, and the contacting liquid. The current flow out of the lower electrode and into the upper electrode is known. Thus, the QCM admittance can be described in terms of its physical properties, surface mass layer, and contacting fluid.

The method of the invention described herein involves characterizing the unperturbed QCM and comparing the differences of those characterizations after the QCM has been loaded with mass and/or liquid. An interesting feature is that the elements that arise from mass and fluid loading are related to the unperturbed QCM parameters. The parasitic capacitance, Cp, depends upon the geometry of the test fixture and the QCM electrode patterns. The static capacitance, Co, arises from internal fields across the quartz, which also excite the mechanical response of the QCM, but Cp arises from fields external to the QCM. Therefore, by measuring the resonance and broadband admittance characteristics, Co can be separated from Cp. The total admittance, Y, can be found from an inspection of the equivalent circuit model and, including the parasitic contribution Cp, where Zm is the motional impedance, is:

Y=jω(Co +Cp)+1/Zm 

This equation assumes that the mass and fluid are contacting only a single side of the QCM; for two-sided contact, certain resistive and motional inductance factors are doubled and the conduction current between electrodes must be considered.

The influence of the mass and fluid perturbations arise from a change in QCM stored energy caused by the perturbation, i.e., resulting from the kinetic energy of the bound mass and/or entrained fluid layer, and the power dissipation because of the radiation of a damped shear wave into the fluid by the oscillating QCM surface, but moving mass does not cause power dissipation. Fluid loading causes an increase in both the motional inductance as well as resistance. In contrast, mass loading increases only the motional inductance.

It has also been determined from the analysis that the effect of mass and fluid loading on charging the resonant frequency is additive and that it is impossible to differentiate changes in surface mass from fluid properties when monitoring only the resonant frequency. The maximum admittance, Ymax, is affected by fluid loading, with the maximum admittance diminishing with ρη where ρ and η are fluid density and viscosity, respectively, but is unaffected by surface mass areal ρs. When the unperturbed QCM has been fully characterized, ρs and ρη can be simultaneously determined from measurements of Δfs and Ymax. Moreover, QCM sensitivity to surface mass can be emphasized over fluid sensitivity by operating at a higher harmonic.

The quartz crystals are 2.54 cm diameter, synthetic AT-cut quartz wafers, and those skilled in the art will understand that other crystalline cuts of quartz, as well as lithium niobate, and certain cuts of lithium tantalate, or any piezoelectric material that allows shear deformations to be electrically excited may be used. The QCMs, nominally 0.33 mm thick, have planar faces that preferably should be lapped and polished. An electrode pattern may be formed by any number of means, including vacuum-evaporating a chromium adhesion layer, followed by a gold layer. The QCM electrode geometry contains a grounded electrode on one side, while the other side contains an electrode at RF potential. Because the electric field is largely confined to the quartz region beneath the smaller electrode, the QCM active area is approximately this smaller electrode area. The larger electrode is contacted by a metal strip that wraps around the right edge of the QCM enabling both electrodes to be contacted from one side, but other contacting methods including two-sided contacts also may be used.

The surface smoothness of the QCMs is critical for obtaining useful admittance measurements. Smoothness is quantified by a measurement of average surface roughness (Ra) using a profilometer. Commercial QCMs have a wide range of Ra values (0.01 to 0.35 μm). It is preferable, however, that the QCM used in the invention have a required Ra ≦0.1 μm. It appears that when surface features are small compared to the fluid decay length (δ=0.15-1.8 μm with fluids tested), the surface behaves as an ideal shear plane interacting with the fluid. Otherwise, alternate mechanisms, such as compressional wave generation, exist for coupling energy from the QCM into the fluid which leads to erroneous results. The QCM roughness leads to increased mass loading because of fluid entrainment and increased dissipation. This results in increased inductance and resistance.

To make electrical measurements, the QCM was mounted in an aluminum RF test fixture, although other test fixtures may be configured to permit, for instance, the fluid to flow across the device. The fixture allows an RF connector to be soldered directly to the smaller electrode and a ground connection to be soldered to the larger electrode. A solder consisting of 1:1 Pb:In may be used to avoid amalgamation and removal of the gold electrode. Pressure contact alone typically resulted in parasitic contact resistance and capacitance, precluding the fitting of measured admittance data to an equivalent circuit. The aluminum fixture has an opening which permits fluid to contact the grounded electrode of the QCM. Immersing the larger electrode in the fluid and keeping that electrode at ground potential prevents fringing RF fields from entering the fluid and causing electrochemical processes and acoustoelectric interactions. It may be necessary to form a fluid seal between the quartz and the test fixture. The QCM test fixture may also be temperature regulated.

A network analyzer measured the complex scattering parameter S11, i.e., reflection magnitude and phase, from which admittance spectra are determined. Measurements were made at multiple points centered about the fundamental and third harmonic resonant frequencies of the dry QCM. To characterize the unloaded QCM at its fundamental resonance, a scan was made over a limited bandwidth to capture the sharp resonance peak, as well as over a bandwidth range to capture the broad-band characteristics. To characterize the unloaded QCM at the third harmonic resonance, scans are also made over limited and broad bandwidths. An incident RF power is applied and the frequencies are scanned. Each measured S11 value was converted to a complex admittance, Y, using the relation: ##EQU1## where Zo is the characteristic impedance of the measurement system. The admittance, Y, can be decomposed into real and imaginary parts (Y=Yr +jYi), from which the admittance magnitude |Y| and phase angle ∠Y are obtained:

|Y|=(Yr 2 +Yi 2)1/2 

∠Y=Tan-1 (Yi /Yr)

For a typical unperturbed QCM in air, the series resonance fs is defined as when |Y| is maximum and ∠Y is zero. Parallel resonance fp occurs when |Y| is minimum and ∠Y is zero. The parameters related to extrinsic QCM properties, i.e., dependent upon QCM geometry, such as thickness h and area A), are determined. The intrinsic properties of the AT-cut quartz are: ρq =2.651 g/cm3, c66 =2.947×1011 dyne/cm2, K2 =7.74×10-3, and ηq =3.5×10-3 g/cm-s. The QCM operated in air is nearly unperturbed, but has a small resistive and inductive contribution because of the non-zero density and viscosity of air.

The invention actually contemplates two methods of obtaining admittance/frequency data. The first method would be to apply an oscillating signal to the QCM at its resonant frequency, and then while oscillating at the resonant frequency, measure the magnitude of the admittance of the QCM. When the mass and/or liquid loading is added, the resonant frequency and maximum admittance are remeasured. From the change in resonant frequency, Δf, and loaded maximum admittance magnitude, Ymax, we can simultaneously determine the surface mass density p2 and contacting liquid density-viscosity product, ρη. This model assumes an "ideal" mass layer that has infinitesimal thickness and stiffness, a condition that is approximated in a number of circumstances. According to the model, the resonant frequency depends on a linear combination of mass and liquid loading terms, while the peak admittance depends only on the liquid loading: ##EQU2## These equations can be solved for surface mass density, ρsf h, where ρf and h are the density and thickness of the mass layer, and the liquid density-viscosity product ρη, where ωo is the angular frequency of 2πf, N is the harmonic number, the c66 factors are quartz stiffness parameters, K2 is an electromechanical coupling factor, ρQ is the quartz density and k1 is the wavenumber which is related to the thickness of the quartz: ##EQU3## Therefore, a measurement of the change in resonant frequency and the admittance at resonance can be used to extract the surface mass density, ρs, and the viscosity-density product, ρη, of the solution. This result, showing how the surface mass and liquid properties can be obtained from the resonant frequency and the admittance, is a crucial part of the technique and has not been previously demonstrated.

A second method contemplates measuring the phase and magnitude of admittance over a frequency range centered around a fundamental or harmonic resonant frequency of the QCM. The data is then fit to the equivalent circuit model of FIG. 3. Fitting the admittance/frequency data to the model allows for determination of equivalent circuit parameters which in turn can be correlated to obtain a solid mass accumulation and the density-viscosity product. A complete theoretical analysis and solution of the boundary value problem for the admittance within a QCM contacting a solid mass layer and a fluid is given in Martin et al., "Characterization of a Quartz Crystal Microbalance with Simultaneous Mass and Liquid Loading," ANAL. CHEM., Vol. 63, No. 20, pp. 2272-2281 Oct. 15, 1991), which is hereby incorporated by reference.

It is to be appreciated that either of the two methods above may be used to measure either the solid mass accumulation and the liquid properties; or both simultaneously. For example, if no solid mass accumulates onto the surface of the QCM, then an accurate measurement of the density-viscosity product is obtained. And if the properties of the fluid do not change or if there is no fluid contacting the QCM, solid mass accumulation may be measured.

To measure the effect of viscous loading on QCM admittance, various solutions contacted the grounded side of the QCM. The solutions were distilled water and three glycerol/water mixtures having distinct viscosity-density products. FIG. 4 shows admittance and frequency data (points) measured at the fundamental resonance as solution properties alone were changed. Several glycerol/water mixtures of varying density ρ and viscosity η contacted the device: (A) air, ρη=2×10-7 ; (B) water, ρη=0.010; (C) 43% glycerol in H2 O, ρη=0.044; (D) 64% glycerol in H2 O, ρη=0.15; (E) 80% glycerol in H2 O, ρη=0.72. With increasing ρη, the admittance magnitude plot shows both a translation of the series resonance peak toward lower frequency, as well as a diminution and broadening of the peak. The parallel or anti-resonant dip in |Y| also becomes less pronounced as ρη increases. The admittance phase plot indicates that phase shifts occurring at fs and fp become less sharp and begin to cancel each other as ρη increases.

The translation of the admittance curves arises from the inductance contribution which represents the kinetic energy of the entrained fluid layer. The broadening and diminution of the resonance peaks arises from the resistance contribution; this element may be called a "radiation resistance" because it represents power dissipation arising from the radiation of a shear wave into the fluid by the oscillating QCM surface. Increasing ρη causes a proportional increase in both energy storage and power dissipation.

To measure the effect of surface mass on QCM admittance, measurements were made before and after the vacuum deposition of a gold film. The gold film was evaporated onto the larger electrode to provide a thin adherent mass layer. The gold thickness was determined from profilometry to be 124 nm. FIG. 5 shows the effect of mass loading on QCM admittance near the fundamental resonance: (A) in air before deposition; (B) in water before deposition; (C) in air after deposition; and (D) in water after deposition of a 124 nm gold layer. It is apparent that the major effect of mass deposition is to translate the admittance curves toward lower frequency without affecting the admittance magnitude. The increased kinetic energy contributed by the mass layer moving synchronously with the QCM surface, and the solid lines in FIG. 5 are predicted admittances. The result of calculations corresponds to a surface mass density ρs =225 μg/cm2. Using the bulk density of gold at 19.30 g/cm3, this surface mass density corresponds to a gold thickness of 117 nm, which is within 6% of the thickness determined from profilometry measurements (124 nm). Thus, electrical admittance measurements can be related directly to mass accumulation on the QCM.

In summary, an analytic expression for the admittance of a QCM simultaneously loaded by a thin mass layer and/or contacting fluid has been derived. Mass and fluid loading lead to distinct admittance/frequency curves that can be used to discriminate between these loading mechanisms. This capability provides for important QCM applications such as fluid phase chemical sensors, viscometers, and plating rate monitors. The measurement of Δf and Ymax is sufficient to determine ρs and ρη; these parameters can be extracted from a QCM oscillator circuit having automatic gain control. However, the nature of the admittance/frequency data leads to greater precision in determining ρs and ρη, particularly at high ρη, where the resonance peak is very broad.

The method of the invention herein has applications in the field of electroless and electrolytic plating, and permits the real-time monitoring of the plating rate and solution specific gravity. Because the specific gravity of the plating solution can increase with time, particularly if the plating bath is overstabilized, it is extremely beneficial to monitor both the plating rate to ensure that the plating thickness is adequate and that the process is in control, and the specific gravity to determine that the mass measurements are accurate.

The invention is also useful in sensor applications where an analyte is deposited as a mass layer onto a substrate from a contacting solution. Real-time-in-situ sol-gel viscosity measurements can now be accomplished economically because only the very thin layer of fluid contacting the QCM will be affected, leaving the bulk fluid unperturbed.

While the invention has been described with respect to several embodiments, and to several applications, it is intended that the invention not be limited to the specifics disclosed therein; rather, the invention is presented as broadly claimed.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US3934059 *Feb 4, 1974Jan 20, 1976Rca CorporationMethod of vapor deposition
US4311725 *Apr 18, 1980Jan 19, 1982National Research Development CorporationControl of deposition of thin films
US4391338 *Apr 4, 1980Jul 5, 1983Harvey PatashnickMicrobalance and method for measuring the mass of matter suspended within a fluid medium
US4477418 *Aug 23, 1983Oct 16, 1984Union Carbide CorporationProcess for adsorption
US4561286 *Jun 28, 1984Dec 31, 1985Laboratoire Suisse De Recherches HorlogeresPiezoelectric contamination detector
US4721874 *Oct 6, 1986Jan 26, 1988Emmert Sans WApparatus and method for determining the viscosity of a fluid sample
US4741200 *Jul 11, 1986May 3, 1988Ford Motor CompanyMethod and apparatus for measuring viscosity in a liquid utilizing a piezoelectric sensor
US4754640 *Mar 17, 1987Jul 5, 1988National Metal And Refining Company, Ltd.Apparatus and method for determining the viscoelasticity of liquids
US4783987 *Feb 10, 1987Nov 15, 1988The Board Of Regents Of The University Of WashingtonSystem for sustaining and monitoring the oscillation of piezoelectric elements exposed to energy-absorptive media
US4788466 *Nov 9, 1987Nov 29, 1988University Of ArkansasPiezoelectric sensor Q-loss compensation
US4862384 *Aug 3, 1987Aug 29, 1989Rockwell International CorporationMethod of measuring the dynamic viscosity of a viscous fluid utilizing acoustic transducer
US4917499 *Oct 3, 1986Apr 17, 1990Hughes Aircraft CompanyApparatus for analyzing contamination
US4999284 *Apr 6, 1988Mar 12, 1991E. I. Du Pont De Nemours And CompanyEnzymatically amplified piezoelectric specific binding assay
Non-Patent Citations
Reference
1G. Sauerbrey, "Verwendung con Schwingquarzen zur Wagung dunner Schichten und zur Mikrowagung," Zeitschrift fur Physik, 1959, vol. 155, pp. 206-222.
2 *G. Sauerbrey, Verwendung con Schwingquarzen zur Wagung dunner Schichten und zur Mikrowagung, Zeitschrift fur Physik , 1959, vol. 155, pp. 206 222.
3K. K. Kanazawa et al., "Evaluation of a Real-Time Rate Monitor For Electroless Nickel Deposition", Plating and Surface Finishing Jul. 1987, pp. 52-55.
4K. K. Kanazawa et al., "Frequency of a Quartz Microbalance in Contact with Liquid," Anal. Chem., 1985, vol. 57, pp. 1770-1771.
5 *K. K. Kanazawa et al., Evaluation of a Real Time Rate Monitor For Electroless Nickel Deposition , Plating and Surface Finishing Jul. 1987, pp. 52 55.
6 *K. K. Kanazawa et al., Frequency of a Quartz Microbalance in Contact with Liquid, Anal. Chem., 1985, vol. 57, pp. 1770 1771.
7K. Kanazawa et al., "The Oscillation Frequency of a Quartz Resonator in Contact with a Liquid," Analytical Chemica Acta, 1985, vol. 175, pp. 99-105.
8 *K. Kanazawa et al., The Oscillation Frequency of a Quartz Resonator in Contact with a Liquid, Analytical Chemica Acta , 1985, vol. 175, pp. 99 105.
9Konash et al., "Piezoelectric Crystals as Detectors in Liquid Chromatography," Anal. Chem., 1980, vol. 52, pp. 1929-1931.
10 *Konash et al., Piezoelectric Crystals as Detectors in Liquid Chromatography, Anal. Chem., 1980, vol. 52, pp. 1929 1931.
11Lu et al. "Investigation of Film-thickness by Oscillating Quartz Resonators with Large Mass Load," J. Appl. Phys., Nov. 1972 vol. 43, No. 11, 4385-4390.
12 *Lu et al. Investigation of Film thickness by Oscillating Quartz Resonators with Large Mass Load, J. Appl. Phys. , Nov. 1972 vol. 43, No. 11, 4385 4390.
13M. D. Ward, "In Situ Interfacial Mass Detection with Piezoelectric Transducers". Science, Aug. 1990, vol. 249, pp. 1000-1007.
14 *M. D. Ward, In Situ Interfacial Mass Detection with Piezoelectric Transducers . Science, Aug. 1990, vol. 249, pp. 1000 1007.
15M. R. Deakin et al., "Prussian Blue Coated Quartz Crystal Microbalance as a Detector for Electroinactive Cations in Aqueous Solution," 1989, Anal. Chem., vol. 61, pp. 290-295.
16 *M. R. Deakin et al., Prussian Blue Coated Quartz Crystal Microbalance as a Detector for Electroinactive Cations in Aqueous Solution, 1989, Anal. Chem., vol. 61, pp. 290 295.
17M. Seo et al., "Study on Corrosion of Copper Thin Film In Air Containing Pollutant Gas by a Quartz Crystal Microbalance," Extended Abstract--178th Meeting of The Electrochemical Society, Seattle, Wash. 1990, Abstract No. 187, pp. 272-273.
18 *M. Seo et al., Study on Corrosion of Copper Thin Film In Air Containing Pollutant Gas by a Quartz Crystal Microbalance, Extended Abstract 178th Meeting of The Electrochemical Society , Seattle, Wash. 1990, Abstract No. 187, pp. 272 273.
19M. Thompson et al. "Liquid-Phase Piezoelectric and Acoustic Transmission Studies of Interfacial Immunochemistry," Anal. Chem., 1986, vol. 58, pp. 1006-1209.
20 *M. Thompson et al. Liquid Phase Piezoelectric and Acoustic Transmission Studies of Interfacial Immunochemistry, Anal. Chem. , 1986, vol. 58, pp. 1006 1209.
21 *Namura et al. Nippon Kagaku Kaishi , 1980, p. 1121.
22Namura et al. Nippon Kagaku Kaishi, 1980, p. 1121.
23R. Schumacher, "The Quartz Microbalance: A Novel Approach to the In-Situ Investigation of Interfacial Phenomena at the Solid/Liquid Junction," Angew. Chem. Int. Ed. Engl., Apr. 1990, vol. 29, No. 4, pp. 329-343.
24 *R. Schumacher, The Quartz Microbalance: A Novel Approach to the In Situ Investigation of Interfacial Phenomena at the Solid/Liquid Junction, Angew. Chem. Int. Ed. Engl. , Apr. 1990, vol. 29, No. 4, pp. 329 343.
25S. Bruckenstein et al., "An In Situ Weighing Study of the Mechanism for the Formation of the Adsorbed Oxygen Monolayer at a Gold Electrode," J. Electroanal. Chem., 1985, vol. 188, pp. 131-136.
26 *S. Bruckenstein et al., An In Situ Weighing Study of the Mechanism for the Formation of the Adsorbed Oxygen Monolayer at a Gold Electrode, J. Electroanal. Chem. , 1985, vol. 188, pp. 131 136.
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US5455475 *Nov 1, 1993Oct 3, 1995Marquette UniversityFor measuring a change of electrical properties
US5571952 *Apr 6, 1995Nov 5, 1996University Of Virginia Patent FoundationElectronic viscometer
US5661233 *Mar 26, 1996Aug 26, 1997Sandia CorporationAcoustic-wave sensor apparatus for analyzing a petroleum-based composition and sensing solidification of constituents therein
US5706840 *Mar 3, 1995Jan 13, 1998Sandia CorporationPrecision cleaning apparatus and method
US5734098 *Mar 25, 1996Mar 31, 1998Nalco/Exxon Energy Chemicals, L.P.Method to monitor and control chemical treatment of petroleum, petrochemical and processes with on-line quartz crystal microbalance sensors
US5741961 *Aug 18, 1993Apr 21, 1998Sandia CorporationQuartz resonator fluid density and viscosity monitor
US5764068 *Jul 25, 1996Jun 9, 1998California Insitute Of TechnologyMethod for measuring mechanical properties of thin films using a resonator in an anti-resonance regime
US5798452 *Apr 25, 1997Aug 25, 1998Sandia CorporationTextured-surface quartz resonator fluid density and viscosity monitor
US5827952 *May 27, 1997Oct 27, 1998Sandia National LaboratoriesMethod of and apparatus for determining deposition-point temperature
US5869763 *Oct 19, 1995Feb 9, 1999The United States Of America As Represented By The Secretary Of The ArmyMethod for measuring mass change using a quartz crystal microbalance
US6053032 *Jan 21, 1998Apr 25, 2000Nalco Chemical CompanySystem and method for determining a deposition rate in a process stream indicative of a mass build-up and for controlling feed of a product in the process stream to combat same
US6106149 *Dec 2, 1998Aug 22, 2000Allan L. SmithMass and heat flow measurement sensor
US6141625 *Jun 4, 1998Oct 31, 2000Dickey-John CorporationViscometer module with crystal resonator-type sensor
US6161420 *Nov 12, 1997Dec 19, 2000Fisher Controls International, Inc.High frequency measuring circuit
US6182499 *Oct 8, 1997Feb 6, 2001Symyx TechnologiesSystems and methods for characterization of materials and combinatorial libraries with mechanical oscillators
US6189367Dec 2, 1998Feb 20, 2001Allan L. SmithApparatus and method for simultaneous measurement of mass and heat flow changes
US6223588Apr 8, 1998May 1, 2001Heriot-Watt UniversityDew point and bubble point measurement
US6223589Apr 26, 1999May 1, 2001Volkswagen AgOil quality sensor
US6247354 *Mar 21, 2000Jun 19, 2001The United States Of America As Represented By The Secretary Of The ArmyTechniques for sensing the properties of fluids with resonators
US6250140Jun 22, 1999Jun 26, 2001Nalco Chemical CompanyMethod for measuring the rate of a fouling reaction induced by heat transfer using a piezoelectric microbalance
US6269686 *Feb 4, 1999Aug 7, 2001Robert Bosch GmbhSensor, in particular for measuring the viscosity and density of a medium
US6306658Dec 14, 1998Oct 23, 2001Symyx TechnologiesParallel reactor with internal sensing
US6336353 *Mar 7, 2001Jan 8, 2002Symyx Technologies, Inc.Method and apparatus for characterizing materials by using a mechanical resonator
US6341629Apr 29, 1999Jan 29, 2002Bp Oil International LimitedTesting device and method of use
US6360585Mar 6, 2000Mar 26, 2002General Electric CompanyMethod and apparatus for determining chemical properties
US6370939 *Feb 16, 2001Apr 16, 2002Allan L. SmithApparatus and method for measurement of mass and heat flow changes
US6375829Mar 7, 2000Apr 23, 2002Nalco Chemical CompanyMetal plated quartz microbalance
US6393895Aug 12, 1998May 28, 2002Symyx Technologies, Inc.Method and apparatus for characterizing materials by using a mechanical resonator
US6401519 *Nov 28, 2000Jun 11, 2002Symyx Technologies, Inc.Systems and methods for characterization of materials and combinatorial libraries with mechanical oscillators
US6455316Apr 13, 2000Sep 24, 2002Symyx Technologies, Inc.For making and characterizing materials; forming reaction mixtures in vessels of parallel apparatus, confining mixture against fluid contamination, injecting fluid into and agitating vessels, and using processor to monitor
US6463787Mar 20, 2000Oct 15, 2002Atotech Deutschland GmbhMounting for a quartz crystal
US6489168Jan 29, 1999Dec 3, 2002Symyx Technologies, Inc.Analysis and control of parallel chemical reactions
US6494079 *Mar 7, 2001Dec 17, 2002Symyx Technologies, Inc.Method and apparatus for characterizing materials by using a mechanical resonator
US6500547Mar 6, 2000Dec 31, 2002General Electric CompanyCoating materials for sensors and monitoring systems, methods for detecting using sensors and monitoring systems
US6526828 *Jun 20, 2001Mar 4, 2003M.S. Tech Ltd.Sensitive and selective method and device for the detection of trace amounts of a substance
US6528026Nov 19, 1998Mar 4, 2003Symyx Technologies, Inc.Multi-temperature modular reactor and method of using same
US6544478Nov 2, 1998Apr 8, 2003Kabushiki Kaisha MeidenshaQCM sensor
US6548026Oct 22, 1998Apr 15, 2003Symyx Technologies, Inc.Parallel reactor with internal sensing and method of using same
US6624708Jun 25, 2002Sep 23, 2003Sandia CorporationActive shunt capacitance cancelling oscillator circuit
US6647764Oct 21, 1999Nov 18, 2003Frank PaulQuartz crystal microbalance with feedback loop for automatic gain control
US6672140 *Mar 23, 2001Jan 6, 2004Cbc Materials Co., Ltd.Method for measuring viscosity of liquid, and method and apparatus for measuring visco-elasticity of liquid
US6722200May 3, 2002Apr 20, 2004California Institute Of TechnologyApparatus and method for ultrasensitive nanoelectromechanical mass detection
US6727096Nov 28, 2000Apr 27, 2004Symyx Technologies, Inc.Analysis and control of parallel chemical reactions
US6755073 *May 8, 2002Jun 29, 2004Robert Bosch GmbhSensor for measuring the viscosity of a liquid
US6787112Nov 28, 2000Sep 7, 2004Symyx Technologies, Inc.Parallel reactor with internal sensing and method of using same
US6818183Apr 29, 2002Nov 16, 2004Symyx Technologies, Inc.For carrying out and monitoring the progress and properties of multiple reactions
US6848299Jul 30, 2003Feb 1, 2005Akubio LimitedQuartz crystal microbalance with feedback loop for automatic gain control
US6864092Nov 28, 2000Mar 8, 2005Symyx Technologies, Inc.Parallel reactor with internal sensing and method of using same
US6865949Jan 31, 2003Mar 15, 2005Hewlett-Packard Development Company, L.P.Transducer-based sensor system
US6880402Oct 26, 2000Apr 19, 2005Schlumberger Technology CorporationDeposition monitoring system
US6886406 *Oct 26, 2000May 3, 2005Schlumberger Technology CorporationDownhole deposition monitoring system
US6890492Nov 28, 2000May 10, 2005Symyx Technologies, Inc.Parallel reactor with internal sensing and method of using same
US6904786Oct 7, 2002Jun 14, 2005Symyx Technologies, Inc.A method and apparatus for measuring properties of a liquid composition includes a mechanical resonator, such as a cantilever, connected to a measurement circuit
US6907785 *Jul 6, 1999Jun 21, 2005Hydramotion LimitedDiagnostic sensor
US6924149Aug 28, 2002Aug 2, 2005Symyx Technologies, Inc.Parallel reactor with internal sensing and method of using same
US6928877 *May 24, 2002Aug 16, 2005Symyx Technologies, Inc.High throughput microbalance and methods of using same
US6942782Apr 22, 2002Sep 13, 2005Nalco CompanyMethod and apparatus for measuring deposit forming capacity of fluids using an electrochemically controlled pH change in the fluid proximate to a piezoelectric microbalance
US6957565Oct 15, 2003Oct 25, 2005Symyx Technologies, Inc.Includes oscillating a tuning fork resonator in a fluid; use in-line monitoring of various physical and electrical properties of fluids flowing in a conduit, e.g. viscosity and dielectric constant
US6978656Oct 31, 2003Dec 27, 2005Hewlett-Packard Development Company, L.P.Transducer-based sensor system and method
US6994827Jun 1, 2001Feb 7, 2006Symyx Technologies, Inc.Shaft driven stirrers; connecting chemical reactors; fluid flow; biosynthesis
US7043969Jun 2, 2003May 16, 2006Symyx Technologies, Inc.Machine fluid sensor and method
US7055377Aug 2, 2001Jun 6, 2006Akubio LimitedQuartz crystal sensor cell
US7073370Oct 15, 2003Jul 11, 2006Symyx TechnologiesMethod and apparatus for characterizing materials by using a mechanical resonator
US7111500Dec 19, 2003Sep 26, 2006Ulvac Inc.Analysis method using piezoelectric resonator
US7117743Jul 31, 2003Oct 10, 2006Hewlett-Packard Development Company, L.P.Multiple-transducer sensor system and method with selective activation and isolation of individual transducers
US7135806Oct 31, 2002Nov 14, 2006Hewlett-Packard Development Company, L.P.Transducer-based sensor system with multiple drive signal variants
US7159463Jun 20, 2002Jan 9, 2007M.S. Tech Ltd.Sensitive and selective method and device for the detection of trace amounts of a substance
US7201041 *Aug 11, 2006Apr 10, 2007Ulvac Inc.Analysis method using piezoelectric resonator
US7207211 *Mar 28, 2005Apr 24, 2007Symyx Technologies, Inc.High throughput microbalance and methods of using same
US7210332Mar 19, 2004May 1, 2007Symyx Technologies, Inc.Mechanical resonator
US7254990May 12, 2006Aug 14, 2007Visyx Technologies, Inc.Machine fluid sensor
US7263874Jun 8, 2005Sep 4, 2007Bioscale, Inc.Methods and apparatus for determining properties of a fluid
US7270005Feb 3, 2005Sep 18, 2007Hewlett-Packard Development Company, L.P.Transducer-based sensor system
US7288229May 8, 2001Oct 30, 2007Symyx Technologies, Inc.To prepare and screen combinatorial libraries in which one can monitor and control process conditions during synthesis and screening
US7302830Jun 5, 2002Dec 4, 2007Symyx Technologies, Inc.Flow detectors having mechanical oscillators, and use thereof in flow characterization systems
US7331232 *Sep 23, 2004Feb 19, 2008Ulvac, Inc.Measurement method and biosensor apparatus using resonator
US7334452 *Jul 23, 2002Feb 26, 2008Visyx Technologies, Inc.Method for characterizing materials by using a mechanical resonator
US7350367Sep 27, 2004Apr 1, 2008Visyx Technologies, Inc.Environmental control system fluid sensing system and method
US7353695May 14, 2007Apr 8, 2008Bioscale, Inc.Methods and apparatus for determining properties of a fluid
US7464580Sep 18, 2006Dec 16, 2008Oakland UniversityIonic liquid high temperature gas sensors
US7568377 *Jul 28, 2006Aug 4, 2009University Of South FloridaHigh frequency thickness shear mode acoustic wave sensor for gas and organic vapor detection
US7721590Mar 19, 2004May 25, 2010MEAS FranceResonator sensor assembly
US7795008Dec 21, 2006Sep 14, 2010M.S. Tech Ltd.An organized, self-assembled monolayer (SAM) on a sensing surface of a sensor device for identifying at least one foreign material from environment; has a piezoelectric crystal element and a sensor
US7844401 *Jan 17, 2008Nov 30, 2010Baker Hushes IncorpatedSystem and method for determining producibility of a formation using flexural mechanical resonator measurements
US7886577Mar 20, 2007Feb 15, 2011Oakland UniversityDevices with surface bound ionic liquids and method of use thereof
US7888134Aug 6, 2007Feb 15, 2011Oakland UniversityImmunosensors: scFv-linker design for surface immobilization
US8088596Oct 9, 2007Jan 3, 2012Oakland UniversityMethod of microorganism detection using carbohydrate and lectin recognition
US8109161Feb 26, 2009Feb 7, 2012Baker Hughes IncorporatedMethods and apparatus for monitoring deposit formation in gas systems
US8133356Jun 19, 2008Mar 13, 2012Nalco CompanyMethod of monitoring microbiological deposits
US8148170Feb 10, 2011Apr 3, 2012Oakland UniversityImmunosensors: scFv-linker design for surface immobilization
US8172836Aug 11, 2008May 8, 2012Tyco Healthcare Group LpElectrosurgical system having a sensor for monitoring smoke or aerosols
US8215156 *Jul 10, 2009Jul 10, 2012Sekonic CorporationMethod for measuring viscosity and/or elasticity of liquid
US8375768May 5, 2009Feb 19, 2013Oakland UniversityIonic liquid thin layer sensor for electrochemical and/or piezoelectric measurements
US8413512 *Nov 16, 2007Apr 9, 2013Ulvac, Inc.Method for agitating liquefied material using quartz crystal oscillator
US8652128Apr 10, 2012Feb 18, 2014Covidien LpElectrosurgical system having a sensor for monitoring smoke or aerosols
US8732938May 19, 2010May 27, 2014MEAS FranceMethod of packaging a sensor
US20100005865 *Jul 10, 2009Jan 14, 2010Sekonic CorporationMethod for measuring viscosity and/or elasticity of liquid
US20100054076 *Nov 16, 2007Mar 4, 2010Atsushi ItohMethod for agitating liquefied material using quartz crystal oscillator
US20120073775 *Nov 28, 2011Mar 29, 2012Prasad DuggiralaMethod for monitoring organic deposits in papermaking
US20120152003 *Dec 23, 2011Jun 21, 2012Arnau Vives AntonioMethod and device for nanogravimetry in fluid media using piezoelectric resonators
US20130245158 *Mar 14, 2013Sep 19, 2013Kemira OyjMethods of measuring a characteristic of a creping adhesive film and methods of modifying the creping adhesive film
CN100408997CJul 6, 1999Aug 6, 2008海德拉运动有限公司Diagnostic sensor
DE19804326B4 *Feb 4, 1998Feb 3, 2011Robert Bosch GmbhSensor insbesondere zur Messung der Viskosität und Dichte eines Mediums
DE19914109A1 *Mar 23, 1999Oct 19, 2000Atotech Deutschland GmbhHalterung für einen Schwingquarz
DE19914109C2 *Mar 23, 1999Oct 11, 2001Atotech Deutschland GmbhHalterung für einen Schwingquarz
EP0649012A1 *Oct 7, 1994Apr 19, 1995Behringwerke AktiengesellschaftBiosensor for measuring changes of viscosity and/or density
EP0750189A1 *Jun 5, 1996Dec 27, 1996Buna Sow Leuna Olefinverbund GmbHMethod for the detection of amphiphilic substances in aqueous matrix and device for carrying out this method
EP0897216A2 *Jul 29, 1998Feb 17, 1999Fraunhofer-Gesellschaft Zur Förderung Der Angewandten Forschung E.V.Piezoelectric resonator, its manufacturing method and its use as a sensor for measuring the concentration of a constituent in a fluid and/or defining the physical properties of the fluid
EP1217359A1 *Dec 20, 2001Jun 26, 2002Total Raffinage Distribution S.A.Method for determining the fouling tendency of a liquid and quartz microbalance for using the method
EP1434047A2 *Dec 23, 2003Jun 30, 2004Ulvac, Inc.Analysis method using piezoelectric resonator
EP1519162A1Sep 24, 2004Mar 30, 2005Ulvac, Inc.Measurement method and biosensor apparatus using resonator
EP1811292A1 *Aug 2, 2001Jul 25, 2007Akubio LimitedQuartz crystal sensor cell
EP2058654A1Feb 23, 2001May 13, 2009Nalco Chemical CompanyApparatus for measuring calcium oxalate scaling
EP2495357A2Nov 25, 2011Sep 5, 2012Technische Universität DresdenDevice and method for measuring the speed or current efficiency when depositing or removing surfaces and process control based on same
WO1997036178A1 *Mar 24, 1997Oct 2, 1997Nalco Chemical CoMethod to monitor and control chemical treatment of petroleum, petrochemical and processes with on-line quartz crystal microbalance sensors
WO1998019156A1 *Oct 17, 1997May 7, 1998Franz DickertOil quality sensor
WO1998041820A1 *Mar 17, 1998Sep 24, 1998Claes FredrikssonMethod and apparatus for measuring properties and processes of cells at surfaces
WO1998045691A1 *Apr 6, 1998Oct 15, 1998Rhoderick William BurgassDew point and bubble point measurement
WO1999028734A1 *Dec 2, 1998Jun 10, 1999Allan L SmithMass and heat flow measurement sensor
WO1999028735A1 *Dec 2, 1998Jun 10, 1999Allan L SmithApparatus and method for simultaneous measurement of mass and heat flow changes
WO2000004370A1 *Jul 6, 1999Jan 27, 2000John Gerrard GallagherDiagnostic sensor
WO2000025118A1 *Oct 21, 1999May 4, 2000Frank PaulQuartz crystal microbalance with feedback loop for automatic gain control
WO2000043773A1 *Dec 23, 1999Jul 27, 2000Franz Ludwig DickertMethod for determining oil quality and oil quality sensor
WO2001009585A1 *Jul 18, 2000Feb 8, 2001Dsm NvMethod for determination of the density of a single fibre
WO2001031329A1Oct 26, 2000May 3, 2001Benoit CouetDeposition monitoring system
WO2001063224A1 *Feb 12, 2001Aug 30, 2001Gabrielli ClaudePiezoelectric material microbalance in liquid medium
WO2001067086A1 *Jan 30, 2001Sep 13, 2001Gen ElectricCoating materials for sensors and monitoring systems, methods for detecting using sensors and monitoring systems
WO2002012873A2 *Aug 2, 2001Feb 14, 2002Frank PaulQuartz crystal microbalance
WO2002090246A2 *May 3, 2002Nov 14, 2002California Inst Of TechnAn apparatus and method for ultrasensitive nanoelectromechanical mass detection
WO2003089920A1Apr 18, 2003Oct 30, 2003Ondeo Nalco CoMeasuring deposit forming capacity with microbalance
WO2010149811A1Jun 18, 2010Dec 29, 2010Universidad Politécnica De ValenciaMethod and device for nanogravimetry in fluid media using piezoelectric resonators
WO2012129098A2 *Mar 16, 2012Sep 27, 2012Baker Hughes IncorporatedMethod for analyzing fluid properties
Classifications
U.S. Classification73/54.41, 73/32.00A, 73/579
International ClassificationG01N29/036, G01N11/16, G01N9/00
Cooperative ClassificationG01N9/002, G01N29/036, G01N2291/02818, G01N2291/014, G01N11/162
European ClassificationG01N29/036, G01N11/16B, G01N9/00B
Legal Events
DateCodeEventDescription
Jan 6, 2005SULPSurcharge for late payment
Year of fee payment: 11
Jan 6, 2005FPAYFee payment
Year of fee payment: 12
Oct 27, 2004REMIMaintenance fee reminder mailed
Sep 14, 2000FPAYFee payment
Year of fee payment: 8
Mar 28, 1997ASAssignment
Owner name: ENERGY, DEPARTMENT OF, UNITED STATES, DISTRICT OF
Free format text: CONFIRMATORY LICENSE;ASSIGNOR:SANDIA CORPORATION;REEL/FRAME:008442/0453
Effective date: 19931202
Aug 26, 1996FPAYFee payment
Year of fee payment: 4
Feb 22, 1994ASAssignment
Owner name: SANDIA CORPORATION, NEW MEXICO
Free format text: LICENSE;ASSIGNOR:UNITED STATES OF AMERICA, THE, AS REPRESENTED BY THE SECRETARY OF THE DEPARTMENT OF ENERGY;REEL/FRAME:006865/0604
Effective date: 19940124
Mar 16, 1992ASAssignment
Owner name: UNITED STATES OF AMERICA, THE, AS REPRESENTED BY T
Free format text: SUBJECT TO LICENSE RECITED;ASSIGNORS:GRANSTAFF, VICTORIA E.;MARTIN, STEPHEN J.;REEL/FRAME:006047/0664
Effective date: 19911021